body {
    background-color: #f1f3f5;
}

.top {
    width: 100%;
    height: 20px;
    font-size: 12px;
    background-color: black;
}

.nav {
    position: sticky;
    top: 0;
    background-color: white;
    height: 80px;
    line-height: 80px;
}
